Sealing and sound absorbing means for air handling apparatus



Nov. 10, 1964 A. D. OCONNELL 3,156,233

SEALING AND souun ABSORBING MEANS FOR AIR HANDLING APPARATUS Filed Sept.16, 1963 INVENTOR. ALVA D. O'CONNELL H\5 ATTORNEY United States Patent3,156,233 SEALING AND SUUND ABSORBENG ll IEANS FOR AIR HANDLINGAPPARATUS Alva D. 0onnell, Tyler, Tex., assignor to General ElectricCompany, a corporation of New York Filed Sept. 16, 1963, Ser. No.309,219 6 Claims. (Cl. 126-410) The present invention relates to a soundabsorbing medium and bottom seating means for an air handling apparatus,and particularly to an upfiow furnace or air handler that is convertibleto either a bottom inlet, a left side inlet or a right side inlet of thereturn air from a duct system in a residence or building Where thefurnace or air handler is installed.

It is well known in the heating field that warm air upflow furnaces haveto be adapted at the time of installation to meet any one of three typesof return inlet possibilities. Some furnace designs are provided with atleast one side opening built into the furnace housing, but

if the installing dealer is faced with the need for a bottom returnopening, it requires time and expense to cut a bottom inlet opening. Ifthe furnace is used with a left or right side inlet opening, the bottomshould be closed or sealed so that dust and dirt from the floor of theoperating area will not be drawn into the inlet plenum chamber of thefurnace due to a negative pressure developed by a motor-blower unittherein which is available for circulating the air past the combustionchamber and heat exchanger or the like.

In addition to the need for a convertible furnace design having thefacility for obtaining a return air opening in either the bottom Wall orone of the two side walls of the furnace, there is also a need forlowering the operating noise level in the inlet plenum chamber. Thisneed has become more pronounced in recent times because the rapid risein the popularity of perimeter distribution has had the effect ofshortening the return air duct and therefore revealing inlet plenumchamber noises more readily. Heretofore these noises were not noticedduring the era of inside supply ducts and return ducts which were longerbecause return air grilles were located on an outside wall. Return airnoises are made even more noticeable where the central return duct hasan extremely short attenuating length between the return air grille andthe furnace proper.

The principal object of the present invention is to pro vide an airhandling apparatus with a facility for obtaining one of several airinlet openings in which a filter medium is installed, while at the sametime benefiting from a sound absorbing medium that may be used as abottom sealing means and/or a noise attenuator in an unused filter rackunder certain conditions.

A further object of the present invention is to provide a warm airupflow furnace with a bottom air inlet opening that is sealed duringshipment by a sound absorbing medium that is used as a supporting pad inthe shipping carton, and Where the absorbing medium is removable so thatit may be installed within the furnace housing so as to attenuate theoperating noises; or alternately may be left in place in the as-shippedposition to provide bottorn sealing, cushioning and attenuation.

The present invention, in accordance with one form thereof, relates toan air handling apparatus for either warming or cooling air where theapparatus has a housing forming a plenum chamber with a bottom airreturn opening and a top air outlet opening. This air inlet or returnopening is adapted to be sealed during shipment by a sheet of softfiberboard that is mounted beneath the apparatus within the shippingcarton. A filter medium is adapted to be positioned within the bottomopening when the apparatus is installed for a bottom inlet return, whilethe center of the sheet of fiberboard may be cut to the size of an inletfilter and positioned along one inner side wall of the plenum chamber toattenuate the noises therein while leaving a square frame of fiberboardmaterial on which the apparatus rests. Moreover, means are provided forforming an air inlet opening in one of the side walls of the housing sothat the filter medium may be transposed to fit within the side inletopening while the sheet of fiberboard may be left in the as-shippedposition to provide sealing, vibration absorption and sound attenuation.

My invention will be better understood from the following descriptiontaken in conjunction with the accompanying drawing and its scope will bepointed out in the appending claims.

FIGURE 1 is an elevational view of a warm air upflow furnace embodyingthe present invention with parts broken away to show the bottom used asa return air opening and a sheet of fiberboard cut into two pieces whereone piece is a square frame on which the furnace rests, while the centerof the sheet is mounted along one side Wall of the plenum chamber forattenuating the noise level.

FIGURE 2 is an elevational view similar to that of FIGURE 1 showing theright side wall of the furnace housing provided with a side air returnopening, while the bottom opening has been sealed by a sheet offiberboard in the as-shipped condition.

FIGURE 3 is an elevational view on a reduced scale showing the furnaceof FIGURES 1 and 2 assembled in a shipping carton with parts of thecarton broken away to show an over-sized sheet of fiberboard mountedbeneath the bottom wall of the furnace to serve as a cushioning pad andspace during shipment.

Turning to a consideration of the drawing and in particular to FIGURE 1there is shown for illustrative purposes a warm air upflow gas-firedfurnace 10 having a housing 11 formed of sheet steel into a box-likeconfiguration having an open bottom wall 12, opposite side walls 13 and14, top wall 15, a front wall 16 as is best seen in FIGURE 2, and aplain back wall (not shown) that is comparable to the front wall 16.While this furnace has been shown and described as a gas-fired furnaceit will be understood by those skilled in this art that fuel oil orelectric resistance heaters could be substituted for the gas fuelwithout departing from the scope of this invention. Moreover, instead ofwarming the air the apparatus could be an air handler having a blowerwith a heat transfer surface or cooling coils for cooling the air Such afurnace housing has supported therein three main components; namely, amotor-blower unit 20 which may be either direct or belt driven, acombustion chamber 21, and a heat exchanger 22. It is considered unnecessary to go into the operating principle of a warm air upflowfurnace in order to explain the present invention, but it is well tohave a little background information before the invention is consideredin detail. This furnace is adapted to be connected in a ducted heatingsystern within a residence or small commercial building, thus it wouldhave an air inlet duct such as duct 23 as well as a heated air outletopening 24 in the top wall 15 of the furnace housing. This return duct23 is connected into a plenum chamber 25 in which the motor-blower unit26 is mounted. The motor is element 26 and it is positioned within thecenter of a blower wheel 2'7. This blower unit will draw air from thereturn duct 23 and supply the necessary volume of air across the heatexchanger 22, and the resultant warm air will exit from the outlet airopening 24 in the top wall 15 of the furnace housing. The front wall 16of the furnace housing is closed by a pair of vertically spacedremovable panels 29 and 39 as is best seen in FIGURE 2 to facilitate theinspection and servicing of the furnace structure and con trols atperiodic intervals.

Looking again at FIGURE 1, the bottom wall 12 of the furnace housing 11is provided with a return or cool air inlet opening 32. In the event thefurnace is provided with a bottom return duct 23, a filter medium 33 inassembled within the housing to overlie the bottom opening 32 and it isheld in place by a suitable filter-holding channel means or racks 34.Similar filter-supporting racks 35 and 36 are located within the plenumchamber on the inner surfaces of the opposite side walls 13 and 14. Inat least one of these racks 35 and 36 is supported a sheet of softfiberboard 37 having been cut to dimensions comparable to those of thefilter medium 33 so that they are interchangeable.

FIGURE 2 of the drawing shows a different mode of installation where thereturn air duct 23 is brought in through the right side wall 14 of thefurnace housing. This is accomplished by cutting out a suitable sizeopening in the imperforate side wall 14 and making the necessary ductconnection to the resulting opening. Then the filter medium 33 istransposed into the filter rack 36 and the sheet of fiberboard 37 isused to seal the bottom opening 32 of the furnace. An over-sized sheetof soft fiberboard 37 is shown in FIGURE 2 fastened to the underside ofthe furnace housing in the as-shipped position. When this sheet is leftin this position upon using a side return inlet the soft fiberboardserves as a resilient pad, a bottom sealing means and a sound attenuatorduring the operation of the blower 20. In FIGURE 1 the fiberboard 37 hasbeen cut into two pieces, a square frame to remain under the furnace anda cut-out sheet taken from the center of the original sheet to form thesheet that slips into one of the filter racks 35 or 36.

FIGURE 3 of the drawing shows the furnace enclosed within a heavy dutycardboard shipping carton 49, where the carton is closed by top andbottom caps 41 and 42 respectively which are held in place on the cartonby metal tension bands or straps 43. Suitable cardboard fillers andcorner posts (not shown) would be assembled in the carton around thefurnace in order to absorb the punishment of shocks that would otherwisebe taken by the furnace during rough handling, storage and shipment. Theover-sized sheet of fiberboard 37 is fastened to the underside of thefurnace It at the factory so as to serve as a cushion means on which thefurnace is supported. Suitable fastening screws (not shown) would extendthrough the fiberboard and into the edge of the bottom opening 32. Ifthe furnace 10 were to be used with a side return air duct, thefiberboard 37 could remain in place beneath the furnace as shown inFIGURE 2. As an alternative for a side return installation, the sheet 37could be removed from beneath the furnace and cut to form a smallersheet of the size of the filter 33 so as to fit into the filter rack 34.

Having described above my invention of a convertible air handlingapparatus or furnace design having either bottom or side wall returnopenings along with a sound absorbing medium located within or below theplenum chamber, it will readily be apparent to those skilled in this artthat the sound absorbing medium would also be used to advantage duringshipment as a cushion means for the furnace within the shipping cartonin order to take full advantage of this material. Moreover, the furnacecould be provided with factory-installed side openings and theseopenings could be sealed with sheets of fiberboard and this would, ofcourse, eliminate the need for the installing dealer to cut the sidewall to form the necessary openings. It has been found expedient when itis necessary to remove the fiberboard 37 from the underside of thefurnace to slip off the lower front panel and tilt the furnace on itsback edge of the bottom wall 12 so that the servicemans foot may be usedto press out the fiberboard since it is a relatively soft compositionsuch as is sold under the trademark Hornasote by the Homasote Company ofTrenton, New Jersey and is used rather widely for interior Wallboardsfor home building. Other suitable materials would be foam rubber andStyrafoam as long as they had some resilience. A type of unsatisfactoryfiberbord material would be Masonite because of its rigidity or hardnesswhich would render it unsatisfactory for sound attenuation.

Modifications of this invention will occur to those skilled in this art,therefore, it is to be understood that this invention is not limited tothe particular embodiments disclosed but that it is intended to coverall modifications which are within the true spirit and scope of thisinvention as claimed.

What i claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A convertible warm air upfiow furnace for heating air circulatedtherethrough from a building structure comprising a furnace housing, acombustion and heat transfer unit as well as a motor-blower unitdisposed in the housing, said housing having a bottom return air openingand a top air outlet opening, a sheet of fiberboard fastened to theunderside of the housing to serve as a cushion during shipment, thehousing having two opposite side walls which are adapted to be formedwith either a left or a right side return opening, and filter racksformed on the inner wall surfaces of the housing over the bottom returnopening as well as for the two possible side return openings, and afilter member adapted to be mounted in one of the three filter racks,the fiberboard sheet formed of soft material so as to be easily cut tothe same size as the filter member and thereby be interchangeabletherewith in any one of the filter racks, whereby, for a bottom return,the fiberboard sheet is adapted to be cut into a square frame tounderline the furnace housing and serve as a cushion seal, the centralsquare cut from the sheet being adapted to be placed in one of the twoside filter racks for noise attenuation, while the filter would bepositioned within the filter racks of the bottom opening, the fiberboardsheet being adapted to seal the bottom opening when one of the sidewalls of the furnace is formed with a side return opening, while thefilter member is adapted to be positioned in the filter rack for saidside opening.

2. A convertible warm air upfiow furnace for residential use in a ductedheating system for heating air circulating through the system, saidfurnace comprising a sheet metal housing containing a plenum chambersupplied with a motor-blower unit, a source of heat energy and a heatexchanger cooperating therewith, said housing having an open bottom wallforming a bottom cool air return opening and a top heated air outletopening, a sheet of fiberboard fastened to the underside of the housingover the bottom opening to serve as a cushion means during shipment, afilter member adapted to be positioned within the housing over thebottom opening when the furnace is provided with a bottom return, thecentral portion of the fiberboard sheet being removable to uncover thebottom opening and being adapted to be positioned along one side Wall ofthe plenum chamber to reduce the noise levels during operation of theblower, and means to form a side return opening in one side wall of theplenum chamber while the filter member is adapted to be mounted in thehousing over said side opening, and the original fiberboard sheet isadapted to seal over the bottom opening of the housing.

3. A convertible warm air furnace for residential use comprising ahousing forming a plenum chamber, a combustion chamber and a heattransfer unit, a motor-blower unit provided in the plenum chamber, thehousing having a top air outlet opening and an open bottom wall adaptedto form a bottom return air opening, a filter member adapted to bepositioned within the housing over the bottom opening when the furnaceis provided with a bottom return, a sheet of soft fiberboard positionedalong one side wall of the plenum chamber to reduce the noise levelsduring the operation of the furnace, and means to establish a sidereturn opening in one side wall of the housing to communicate with theplenum chamber, the filter member being adapted to be mounted in saidside return opening, and the fiberboard sheet being adapted to seal thebottom opening in the housing as well as to attenuate the noises andvibrations during the blower operation.

4. A convertible air handling apparatus having a housing forming aplenum charnber with a motor-blower unit located therein, the housingincluding an open bottom wall forming a bottom air inlet opening, anopening in the top wall forming an air outlet opening, a filter mediumadapted to be positioned within the bottom opening when the apparatus isprovided with a bottom inlet, at least one sheet of soft fiberboardpositioned along a side wall of the plenum chamber to reduce the noiselevel therein, the said sheet of fiberboard also being adapted to befastened to the underside of theapparatus when the apparatus is sealedin a shipping carton to cushion the apparatus during shipment, thefiberboard sheet being adapted to remain in the as-shipped position Whenthe air handler is installed and running with a side return airconnection so as to provide a sealing cushioning and noise attenutatingmeans.

5. A convertible air handling apparatus having a metal housing enclosinga plenum chamber that includes a motor-blower unit, the housing havingan open bottom wall that forms a bottom air inlet opening, an opening inthe top wall of the housing forming an air outlet opening, a filtermedium adapted to be positioned Within the bottom opening when theapparatus is provided with a bottom inlet, at least one sheet offiberboard positioned along a side wall of the plenum chamber toattentuate the noises therein, means for forming an air inlet opening inone of the side walls of the housing, the said filter medium beingadapted to be transposed to fit within the side inlet opening, while thesaid sheet of fiberboard is adapted to be located in the bottom openingto seal the bottom opening of the housing and continue to attenuate thenoise level.

6. A convertible air handling apparatus for use with a duct system fortreating air circulating through the system, said apparatus comprising asheet metal housing containing a plenum chamber supplied with amotorblower unit, said housing having an open bottom wall forming abottom air return opening and a top air outlet opening, a sheet ofresilient material fastened to the underside of the housing over thebottom opening to serve as a cushion means during shipment, a filtermember adapted to be positioned within the housing over the bottomopening when the furnace is provided with a bottom return, the centralportion of the resilient sheet being removable to uncover the bottomopening and being adapted to be positioned along one side wall of theplenum chamber to reduce the noise levels during operation of theblower, and means to form a side return opening in at least one sidewall of the plenum chamber, a filter medium adapted to be positionedover the air return opening, while the original resilient sheet isadapted to be used as a cushion pad under the housing as well as an airseal and a means to attenuate the noise level.

References Cited in the file of this patent UNITED STATES PATENTS2,118,328 Roland May 24, 1938 FOREIGN PATENTS 961,758 Germany Apr. 11,1957

5. A CONVERTIBLE AIR HANDLING APPARATUS HAVING A METAL HOUSING ENCLOSINGA PLENUM CHAMBER THAT INCLUDES A MOTOR-BLOWER UNIT, THE HOUSING HAVINGAN OPEN BOTTOM WALL THAT FORMS A BOTTOM AIR INLET OPENING, AN OPENING INTHE TOP WALL OF THE HOUSING FORMING AN AIR OUTLET OPENING, A FILTERMEDIUM ADAPTED TO BE POSITIONED WITHIN THE BOTTOM OPENING WHEN THEAPPARATUS IS PROVIDED WITH A BOTTOM INLET, AT LEAST ONE SHEET OFFIBERBOARD POSITIONED ALONG A SIDE WALL OF THE PLENUM CHAMBER TOATTENTUATE